Magnetic memory cell and magnetic random access memory

ABSTRACT

A magnetic memory cell  1  is provided with a magnetic recording layer  10  which is a ferromagnetic layer and a pinned layer  30  connected with the magnetic recording layer  10  through a non-magnetic layer  20 . The magnetic recording layer  10  has a magnetization inversion region  13 , a first magnetization fixed region  11  and a second magnetization fixed region  12 . The magnetization inversion region  13  has a magnetization whose orientation is invertible and overlaps the pinned layer  30 . The first magnetization fixed region  11  is connected with a first boundary B 1  in the magnetization inversion region  13  and a magnetization orientation is fixed on a first direction. The second magnetization fixed region  12  is connected with a second boundary B 2  in magnetization inversion region  13  and a magnetization orientation is fixed on a second direction. The first direction and the second direction are opposite to each other.

REFERENCE TO RELATED APPLICATION

This is a divisional application of U.S. patent application Ser. No.12/443,349 filed Mar. 27, 2009 and claims the benefit of its priority.

TECHNICAL FIELD

The present invention relates to a magnetic random access memory inwhich magnetic memory cells are integrated, and a read/write method of adata from/to the magnetic random access memory.

BACKGROUND ART

A magnetic random access memory (MRAM) is a non-volatile memory that ishopeful from the viewpoints of a high integration and a high speedoperation. As a method of writing, data to the MRAM, conventionally, an“Asteroid method” (for example, U.S. Pat. No. 5,640,343) and a “Togglemethod” (for example, U.S. Pat. No. 6,545,906, Japanese PatentApplication Publication JP-P2005-505889A) are known. According to thesewrite methods, a switching magnetic field required to switchmagnetization of a free layer becomes greater in substantially inverselyproportional to a memory cell size. In short, there is known a tendencythat a write current increases as the memory cell is made smaller.

As the write method that can suppress the increase of a write current inassociation with a fine structure, there are proposed a “Spin TransferMethod” (for example, Japanese Patent Application Publication(JP-P2005-093488A), and “Research Trends in Spin Transfer MagnetizationSwitching” (Japanese Applied Magnetic Academic Society Journal, Vol. 28,No. 9, 2004) by K. Yagami and Y. Suzuki. According to the spin transfermethod, a spin-polarized current is injected to a ferromagneticconductor, and the magnetization is switched by the directly interactionbetween a spin of a conductive electron as a carrier and magnetic momentof the conductor (hereinafter, to be referred to as a spin transfermagnetization switching). The outline of the spin transfer magnetizationswitching will be described below with reference to FIG. 1.

In FIG. 1, a magneto-resistance element contains a free layer 101, apinned layer 103, and a tunnel barrier layer 102, which is anon-magnetic layer and put between the free layer 101 and the pinnedlayer 103. Here, the pinned layer 103 whose magnetization orientation isfixed is formed to be thicker than the free layer 101 and functions as amechanism (spin filter) for generating the spin-polarized current. Astate in which the magnetization orientations of the free layer 101 andthe pinned layer 103 are parallel is correlated to a data “0”, and astate in which they are anti-parallel is correlated to a data “1”.

The spin transfer magnetization switching shown in FIG. 1 is attained bya CPP (Current Perpendicular to Plane) method, and a write current isvertically injected to a film surface. Specifically at a time of atransition from the data “0” to the data “1”, a current flows from thepinned layer 103 to the free layer 101. In this case, electrons havingthe same spin state as the pinned layer 103 serving as a spin filtermove from the free layer 101 to the pinned layer 103. Thus, themagnetization of the free layer 101 is switched through a spin transfereffect (exchange of a spin angular motion amount). On the other hand, ata time of transition from the data “1” to the data “0”, the currentflows from the free layer 101 to the pinned layer 103. In this case,electrons having the same spin state as the pinned layer 103 serving asthe spin filter move from the pinned layer 103 to the free layer 101.The magnetization of the free layer 101 is switched through the spintransfer effect.

In this way, in the spin transfer magnetization switching, the write ofdata is carried out through the movement of the spin electrons. Themagnetization orientation of the free layer 101 can be defined inaccordance with a direction of spin-polarized current that is verticallyinjected to the film surface. Here, a threshold at the time of write(magnetization switching) is known to depend on a current density. Thus,as a memory cell size is contracted, the write current necessary for themagnetization switching decreases. In association with the finerstructure of the memory cell, the write current decreases. Thus, thespin transfer magnetization switching is important in attaining thelarger capacity of the MRAM.

As a related art, U.S. Pat. No. 6,834,005 discloses a magnetic shiftregister that uses the spin transfer. This magnetic shift registerstores a data by using a domain wall inside a magnetic substance body.In the magnetic substance body with many regions (magnetic domains), thecurrent is injected to pass through the domain wall, and the domain wallis moved by the current. The magnetization orientation in each domain isused as a record data. Such a magnetic shift register is used to record,for example, a large quantity of serial data. It should be noted thatthe motion of the domain wall inside the magnetic substance body is alsoreported in “Real-Space Observation of Current-Driven Domain Wall Motionin Submicron Magnetic Wires” (PRL, Vol. 92, pp. 077205-1-0077205-4,2004) by A. Yamaguchi, et al.

As a related art, Japanese Patent Application Publication(JP-P2006-73930A) discloses a method of changing a magnetization stateof a magneto-resistance effect element by using the domain wall motion,and a magnetic memory element and a solid magnetic memory using themethod. This magnetic memory element has a first magnetic layer, amiddle layer and a second magnetic layer, and records data as themagnetization orientations of the first magnetic layer and the secondmagnetic layer. In this magnetic memory element, the magnetic domainsthat are magnetized anti-parallel to each other and the domain wall thatseparates those magnetic domains are steadily formed inside at least onemagnetic layer, and the domain wall is moved inside the magnetic layer.As a result, the positions of the magnetic domains adjacent to eachother are controlled for data recording.

As a related art, Japanese Patent Application Publication(JP-P2005-191032A) discloses a magnetic memory device and a method ofwriting a data. This magnetic memory device includes a conductivemagnetization fixed layer to which a fixed magnetization is given, atunnel insulating layer formed on the magnetization fixed layer, aconductive magnetization free layer that has a junction section formedon the magnetization fixed layer through the tunnel insulating layer,domain wall pinned sections formed adjacently to a pair of ends of thejunction section, and a pair of magnetization fixed sections which areadjacent to the domain wall pinned sections and to which the fixedmagnetizations of orientations opposite to each other are given, and apair of magnetic data write terminals that are electrically connected toa pair of magnetization fixed sections, and are provided to flow to themagnetization free layer, a current which penetrates through thejunction section of the magnetization free layer, a pair of domain wallpinned sections and a pair of the magnetization fixed sections.

As a related art, Japanese Patent Application Publication(JP-P2005-150303A) discloses a magneto-resistance effect element and amagnetic memory device. This magneto-resistance effect element has aferromagnetic tunnel junction that has a 3-layer structure of a firstferromagnetic layer/a tunnel barrier layer/a second ferromagnetic layer.The first ferromagnetic layer is greater in coercive force than thesecond ferromagnetic layer. A tunnel conductance is changed inaccordance with the relative angle of the magnetizations between the twoferromagnetic layers. This magneto-resistance effect element ischaracterized in that the magnetization of the end of the secondferromagnetic layer is fixed to a direction having a componentorthogonal to a magnetization easiness axis direction of the secondferromagnetic layer.

DISCLOSURE OF INVENTION

An object of the present invention is to provide a new data write methodwith regard to the MRAM.

Another object of the present invention is to provide an MRAM that cansuppress the deterioration of a tunnel barrier layer in an MTJ, and adata write method.

Still another object of the present invention is to provide an MRAM thatcan decrease a write current in association with contraction of a memorycell size, and a data write method.

Still another object of the present invention is to provide an MRAM thatcan increase a write speed in association with contraction of a memorysize, and a data write method.

Those objects of this invention and the objects other than them can beeasily verified from the following descriptions and the attacheddrawings.

A magnetic memory cell of the present invention contains a magneticrecording layer that is a ferromagnetic layer, and a pinned layerconnected to the magnetic recording layer through a non-magnetic layer.The magnetic recording layer has a magnetization inversion region, afirst magnetization fixed region and a second magnetization fixedregion. The magnetization inversion region has a magnetization whoseorientation can be switched in a first direction or a second directionand overlaps with the pinned layer. The first magnetization fixed regionis connected to a first boundary of the magnetization inversion region,and its magnetization orientation is fixed to the first direction. Thesecond magnetization fixed region is connected to a second boundary ofthe magnetization inversion region, and its magnetization orientation isfixed to a second direction. The first direction and the seconddirection are opposite to each other.

A magnetic memory cell of the present invention has a magneto-resistanceelement, a first magnetization fixed section and a second magnetizationfixed section. The magneto-resistance element has a free layer, a pinnedlayer, and a non-magnetic layer sandwiched between the free layer andthe pinned layer. The first magnetization fixed section is connected tothe free layer on a first boundary, and its magnetization orientation isfixed to a first direction. The second magnetization fixed section isconnected to the free layer on a second boundary, and its magnetizationorientation is fixed to a second direction. The first direction and thesecond direction are opposite to each other, namely, a direction towardsthe free layer or a direction from the free layer. The current, whichflows between the first magnetization fixed section and the secondmagnetization fixed section, causes a domain wall to be moved betweenthe first boundary and the second boundary in the free layer.

A magnetic random access memory of the present invention contains theforegoing magnetic memory cell, a word line connected to the magneticmemory cell, and a bit line connected to the magnetic memory cell.

An operation method of a magnetic random access memory of the presentinvention is provided. The magnetic random access memory has a magneticmemory cell. The magnetic memory cell contains a magnetic recordinglayer that is the ferromagnetic layer; and a pinned layer connected tothe magnetic recording layer through a non-magnetic layer. The magneticrecording layer has a magnetization inversion region that has amagnetization invertible in a first direction or second direction andoverlaps the pinned layer, a first magnetization fixed region connectedto a first boundary of the magnetization inversion region and whosemagnetization orientation is fixed to the first direction, and a secondmagnetization fixed region connected to a second boundary of themagnetization inversion region and whose magnetization orientation isfixed to the second direction. The first direction is parallel oranti-parallel to the magnetization orientation of the pinned layer. Theoperation method of the magnetic random access memory includes (A)making a first write current flow from the first magnetization fixedregion through the magnetization inversion region to the secondmagnetization fixed region, when a first data is written; and (B) makinga second write current flow from the second magnetization fixed regionthrough the magnetization inversion region to the first magnetizationfixed region, when a second data is written.

An operation method of a magnetic random access memory of the presentinvention is provided. The magnetic random access memory has a magneticmemory cell. The magnetic memory cell contains a magnetic recordinglayer that is a ferromagnetic layer, and a pinned layer connected to themagnetic recording layer through a non-magnetic layer. The magneticrecording layer has a magnetization inversion region which overlaps thepinned layer and in which the domain wall is moved; a firstmagnetization fixed region connected to a first boundary of themagnetization inversion region and whose magnetization orientation isfixed to a first direction; and a second magnetization fixed regionconnected to a second boundary of the magnetization inversion region andwhose magnetization orientation is fixed to a second direction. Thefirst direction is parallel or anti-parallel to the magnetizationorientation of the pinned layer. The operation method of the magneticrandom access memory includes (A) making a first write current flow fromthe first magnetization fixed region to the second magnetization fixedregion to move the domain wall inside the magnetic recording layer tothe first boundary, when the first data is written; and (B) making asecond write current flow from the second magnetization fixed region tothe first magnetization fixed region to move the domain wall to thesecond boundary, when the second data is written.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram showing data write based on a conventional spintransfer method;

FIG. 2 is a diagram showing one example of a structure of a magneticmemory cell according to a first exemplary embodiment of the presentinvention;

FIG. 3 is a diagram showing another example of the structure of themagnetic memory cell according to the first exemplary embodiment of thepresent invention;

FIG. 4A is a plan view showing one example of the structure of themagnetic memory cell shown in FIG. 2;

FIG. 4B is a plan view showing another example of the structure of themagnetic memory cell shown in FIG. 2;

FIG. 5 is a plan view showing the principle of the data write to themagnetic memory cells shown in FIG. 4A and FIG. 4B;

FIG. 6A is a plan view showing one example of a different structure ofthe magnetic memory cell shown in FIG. 2;

FIG. 6B is a plan view showing another example of the differentstructure of the magnetic memory cell shown in FIG. 2;

FIG. 7 is a plan view showing the principle of the data write to themagnetic memory cell shown in FIG. 6A and FIG. 6B;

FIG. 8 is a plan view schematically showing a circuit configuration ofthe magnetic memory cell according to the first exemplary embodiment;

FIG. 9A is a sectional view schematically showing the circuitconfiguration of the magnetic memory cell according to the firstexemplary embodiment and corresponding to FIG. 2;

FIG. 9B is a section view schematically showing the circuitconfiguration of the magnetic memory cell according to the firstexemplary embodiment and corresponding to FIG. 3;

FIG. 10A is a table summarily showing a data reading/writing methodaccording to the first exemplary embodiment and corresponding to FIG.4A, FIG. 4B and FIG. 5;

FIG. 10B is a table summarily showing a data reading/writing methodaccording to the first exemplary embodiment and corresponding to FIG.6A, FIG. 6B and FIG. 7;

FIG. 11 is a circuit block diagram showing one example of a circuitconfiguration, corresponding to FIG. 9A, of the MRAM according to thefirst exemplary embodiment;

FIG. 12 is a side view showing one example of a method of fixing amagnetization orientation in the magnetization fixing region;

FIG. 13 is a side view showing another example of a method of fixing amagnetization orientation in the magnetization fixing region;

FIG. 14 is a side view showing still another example of a method offixing the magnetization orientation in the magnetization fixing region;

FIG. 15 is a side view showing still another example of the method tofix a magnetization orientation in the magnetization fixing region;

FIG. 16 is a side view showing still another example of a method offixing a magnetization orientation in the magnetization fixing region;

FIG. 17 is a side view showing still another example of a method offixing a magnetization orientation in the magnetization fixing region;

FIG. 18A is a plan view schematically showing a circuit configuration ofanother magnetic memory cell according to the first exemplaryembodiment;

FIG. 18B is a plan view schematically showing a circuit configuration ofstill another magnetic memory cell according to the first exemplaryembodiment;

FIG. 19A is a circuit block diagram showing one example of the circuitconfiguration, corresponding to FIG. 18A, of the MRAM according to thefirst exemplary embodiment;

FIG. 19B is a circuit block diagram showing one example of the circuitconfiguration, corresponding to FIG. 18B, of the MRAM according to thefirst exemplary embodiment;

FIG. 20A is a plan view showing one example of a structure of a magneticmemory cell according to a second exemplary embodiment of the presentinvention;

FIG. 20B is a side view showing one example of the structure of themagnetic memory cell according to the second exemplary embodiment of thepresent invention;

FIG. 21A is a plan view showing another example of the structure of themagnetic memory cell according to the second exemplary embodiment of thepresent invention;

FIG. 21B is a side view showing another example of the structure of themagnetic memory cell according to the second exemplary embodiment of thepresent invention;

FIG. 22 is a plan view showing one example of a structure of a magneticmemory cell according to a third exemplary embodiment of the presentinvention;

FIG. 23 is a section view showing one example of a structure of amagnetic memory cell according to a fourth exemplary embodiment of thepresent invention;

FIG. 24 is a plan view showing one example of a structure of a magneticmemory cell according to a fifth exemplary embodiment of the presentinvention;

FIG. 25 is a sectional view showing one example of the structure of themagnetic memory cell according to the fifth exemplary embodiment of thepresent invention;

FIG. 26 is a plan view showing the principle of the data write to amagnetic memory cell according to a sixth exemplary embodiment of thepresent invention; and

FIG. 27 is a circuit block diagram showing one example of a circuitconfiguration of the MRAM according to the sixth exemplary embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION

A magnetic memory cell, a magnetic random access memory, and a datawriting method of the magnetic random access memory according to thepresent invention will be described below with reference to the attacheddrawings.

1. FIRST EXEMPLARY EMBODIMENT 1-1. Structure of Magnetic Memory Cell andWrite Principle

FIG. 2 is a perspective view showing an example of the configuration ofa magnetic memory cell 1 (magneto-resistance element) according to thefirst exemplary embodiment of the present invention. The magnetic memorycell 1 contains a magnetic recording layer 10 and a pinned layer 30,which are ferromagnetic layers, and a tunnel barrier layer 20 which is anon-magnetic layer. The tunnel barrier layer 20 is put between themagnetic recording layer 10 and the pinned layer 30. The magneticrecording layer 10, the tunnel barrier layer 20 and the pinned layer 30form a magnetic tunnel junction (MTJ).

The tunnel barrier layer 20 is a thin insulating layer and formed byoxidizing an Al film, for example. The pinned layer 30 is a laminationfilm of, for example, CoFe/Ru/CoFe/PtMn, and its magnetizationorientation is fixed. The magnetic recording layer 10 is made of, forexample, CoFe and functions equivalent to a free layer.

As shown in FIG. 2, the magnetic recording layer 10 according to thisexemplary embodiment has three different regions, i.e., a firstmagnetization fixed region 11, a second magnetization fixed region 12and a magnetization inversion region 13. The first magnetization fixedregion 11 is formed to extend in a Y-direction, and its magnetizationorientation is fixed. Similarly, the second magnetization fixed region12 is formed to extend in the Y-direction, and its magnetizationorientation is opposite to the magnetization orientation in the firstmagnetization fixed region 11. On the other hand, the magnetizationinversion region 13 is formed to extend in an X-direction and has aninvertible magnetization. The magnetization orientation of themagnetization inversion region 13 is equal to that of one of the firstmagnetization fixed region 11 and the second magnetization fixed region12. Also, this magnetization inversion region 13 is formed to overlapthe pinned layer 30. In other words, a part of the magnetizationinversion region 13 in the magnetic recording layer 10 is connectedthrough the tunnel barrier layer 20 to the pinned layer 30.

The first magnetization fixed region 11, the second magnetization fixedregion 12 and the magnetization inversion region 13 are formed on thesame flat surface (XY plane) in case of FIG. 2. FIG. 4A and FIG. 4B areschematic diagrams showing examples of the shapes and magnetizationorientations of the magnetic recording layer 10 on the XY plane. In thisexemplary embodiment, the first magnetization fixed region 11 and thesecond magnetization fixed region 12 are formed to be approximatelyparallel to each other along the Y-direction. The magnetizationinversion region 13 is formed along the X-direction for linkage betweenthe first magnetization fixed region 11 and the second magnetizationfixed region 12. The first magnetization fixed region 11 and themagnetization inversion region 13 are in contact with each other in afirst boundary B1. The second magnetization fixed region 12 and themagnetization inversion region 13 are connected to each other in asecond boundary B2. In the magnetization inversion region 13, the firstboundary B1 and the second boundary B2 are located to oppose to eachother. In other words, the first and second magnetization fixed regions11 and 12 and the magnetization inversion region 13 are formed to have a“concave-shaped (angular U-shaped)” form (FIG. 4A) or an “H-shaped” form(FIG. 4B).

In FIG. 4A and FIG. 4B, the magnetization orientations of the respectiveregions are also indicated by arrow marks. Moreover, a projection of thepinned layer 30 and its magnetization orientation are also indicated bydotted lines and dotted line arrow marks. It is supposed that themagnetization orientation of the pinned layer 30 is fixed to the+Y-direction, and the magnetization orientation of the firstmagnetization fixed region 11 is fixed to the +Y-direction. In thiscase, the magnetization orientation of the second magnetization fixedregion 12 is fixed to the −Y-direction. In short, the firstmagnetization fixed region 11 and the second magnetization fixed region12 are formed such that their magnetization orientations are opposite toeach other. It should be noted that “Fixation of Magnetization” will bedescribed later (Paragraph 1-3).

On the other hand, the magnetization orientation of the magnetizationinversion region 13 can be switched, and it is the +Y-direction or the−Y-direction. In short, the magnetization of the magnetization inversionregion 13 is allowed to be parallel or anti-parallel to themagnetization of the pinned layer 30. This is attained by settingcrystalline magnetic anisotropy for the ±Y-direction of themagnetization inversion region 13. For example, when the magnetizationorientation of the magnetization inversion region 13 is the−Y-direction, namely, when the magnetization is equal to the secondmagnetization fixed region 12, the first magnetization fixed region 11forms one magnetic domain, and the magnetization inversion region 13 andthe second magnetization fixed region 12 forms a different magneticdomain. In short, a “Domain Wall” is formed on the first boundary B1. Onthe other hand, when the magnetization orientation of the magnetizationinversion region 13 is the +Y-direction, namely, when the magnetizationis equal to the first magnetization fixed region 11, the firstmagnetization fixed region 11 and the magnetization inversion region 13forms one magnetic domain, and the second magnetization fixed region 12forms a different magnetic domain. In short, the domain wall is formedon the second boundary B2.

In this way, the magnetization of the magnetization inversion region 13is oriented to the first direction (e.g., −Y-direction) or the seconddirection (e.g., +Y-direction). In the magnetic recording layer 10, thedomain wall is formed on the first boundary B1 or the second boundary82. This is because the magnetization orientation of the firstmagnetization fixed region 11 and the magnetization orientation of thesecond magnetization fixed region 12 are opposite.

It should be noted that FIG. 3 is a perspective view showing anotherexample of the configuration of the magnetic memory cell 1 according tothe first exemplary embodiment of the present invention. In this exampleof the magnetic memory cell 1, the first magnetization fixed region 11and the second magnetization fixed region 12 are formed on the same flatsurface (XY plane), and the magnetization inversion region 13 is put onthem. However, the magnetic arrangements are similar to those shown inFIG. 4A and FIG. 4B, and the descriptions are omitted.

The principle of writing a data into the magnetic memory cell 1 will bedescribed below. According to this exemplary embodiment, the write ofthe data is carried out by the spin transfer method (Spin Transfer DataWriting).

STRUCTURE EXAMPLE 1

FIG. 5 is a diagram schematically showing the principle of writing adata into the magnetic memory cell 1 having the structure shown in FIG.2, FIG. 3 and FIG. 4B. It should be noted that a case of FIG. 4A is alsosimilar. Here, the state in which the magnetization orientations of themagnetization inversion region 13 and the pinned layer 30 are parallelis related to the data “0”. In the data “0”, the magnetizationorientation of the magnetization inversion region 13 is the+Y-direction, and a domain wall DW exists on the second boundary B2. Onthe other hand, the state in which the magnetization orientations of themagnetization inversion region 13 and the pinned layer 30 areanti-parallel is related to the data “1”. In the data “1” state, themagnetization orientation of the magnetization inversion region 13 isthe −Y-direction, and the domain wall DW exists on the first boundaryB1.

In this exemplary embodiment, a write current I_(W) does not flow in thedirection penetrating through the MTJ, and it flows inside the magneticrecording layer 10. Specifically, when the data “1” is written (firstwrite), a first write current I_(W1) flows from the first magnetizationfixed region 11 through the magnetization inversion region 13 to thesecond magnetization fixed region 12. In this case, the electrons (spinelectrons) are injected from the second magnetization fixed region 12 tothe magnetization inversion region 13. The injected electrons haveinfluence on a magnetic moment of the magnetization inversion region 13by their spin. As a result, the magnetization orientation of themagnetization inversion region 13 is switched to the direction of thesecond magnetization fixed region 12. In short, the spin transfer effectcauses the magnetization of the magnetization inversion region 13 to beswitched to change its magnetization orientation into the −Y-direction(Spin Transfer Magnetization Switching).

On the other hand, when the data “0” is written (second write), a secondwrite current I_(W2) flows from the second magnetization fixed region 12through the magnetization inversion region 13 to the first magnetizationfixed region 11. In this case, the electrons are injected or transferredfrom the first magnetization fixed region 11 to the magnetizationinversion region 13. As a result, the magnetization of the magnetizationinversion region 13 is switched, and its magnetization orientation ischanged to the +Y-direction. In this way, according to this exemplaryembodiment, the magnetization orientation of the magnetization inversionregion 13 is switched by the write currents I_(W1) and I_(W2) thatflatly flow inside the magnetic recording layer 10. The firstmagnetization fixed region 11 and the second magnetization fixed region12 functions as a supply source of the electrons having the differentspins.

The above-mentioned write operation can be described from the viewpointof “Domain Wall Motion”. When the data “1” is written, the electrons aremoved from the second magnetization fixed region 12 to the firstmagnetization fixed region 11. At this time, the domain wall DW is movedfrom the second boundary B2 to the first boundary B1 in correspondencewith the motion direction of the electrons. On the other hand, when thedata “0” is written, the electrons are moved from the firstmagnetization fixed region 11 to the second magnetization fixed region12. At this time, the domain wall DW is moved from the first boundary B1to the second boundary B2 in correspondence with the motion direction ofthe electrons. In short, the domain wall DW inside the magneticrecording layer 10 is reciprocated in the manner of “Seesaw” or “FlowMeter” between the first boundary B1 and the second boundary B2. Sincethe domain wall DW is moved inside the magnetization inversion region13, the magnetization inversion region 13 can be also referred to as a“Domain Wall Motion Region”. The magnetic memory cell 1 according tothis exemplary embodiment is said to store the data, depending on theposition of the domain wall DW.

As mentioned above, since the write currents IW₁ and IW₂ do notpenetrate through the MTJ, the deterioration of the tunnel barrier layer20 in the MTJ is suppressed. Also, since the data write is carried outby the spin transfer method, the write currents IW₁ and IW₂ can bedecreased in association with the contraction of the memory cell size.Moreover, as the memory cell size is contracted, the motion distance ofthe domain wall DW is made shorter. Thus, the write speed is increasedin association with the finer structure of the memory cell.

It should be noted that the read of the data is as follows. When thedata is read, the read current is supplied to flow between the pinnedlayer 30 and the magnetization inversion region 13. For example, theread current flows from one of the first magnetization fixed region 11and the second magnetization fixed region 12 through the magnetizationinversion region 13 and the tunnel barrier layer 20 to the pinned layer30. Or, the read current flows from the pinned layer 30 through thetunnel barrier layer 20 and the magnetization inversion region 13 to oneof the first magnetization fixed region 11 and the second magnetizationfixed region 12. A resistance value of the magneto-resistance element isdetected based on the read current or the read potential, and themagnetization orientation of the magnetization inversion region 13 issensed.

STRUCTURE EXAMPLE 2

The magnetization orientation of the first magnetization fixed region 11and the magnetization orientation of the second magnetization fixedregion 12 are not limited to the orientations shown in FIG. 4A and FIG.4B. FIG. 6A and FIG. 6B are diagrams schematically showing anotherexample of the shape and magnetization orientation of the magneticrecording layer 10 on the XY plane. The magnetization orientation of thefirst magnetization fixed region 11 and the magnetization orientation ofthe second magnetization fixed region 12 may be opposite. FIG. 7 is adiagram schematically showing the principle of writing the data to themagnetic memory cell 1 of the structure shown in FIG. 2, FIG. 3 and FIG.6B. It should be noted that a case of FIG. 6A is also similar. FIG. 7corresponds to FIG. 5, and the same description is properly omitted.

The magnetization orientation of the first magnetization fixed region 11is fixed to the −Y-direction. Also, the magnetization orientation of thesecond magnetization fixed region 12 is fixed to the +Y-direction. Inshort, the magnetization of the first magnetization fixed region 11 andthe magnetization of the second magnetization fixed region 12 areoriented opposite to each other. Also, the magnetization orientation ofthe pinned layer 30 is assumed to be fixed to the +Y-direction. In thedata “0” state, the magnetization orientation of the magnetizationinversion region 13 is the +Y-direction, and the domain wall DW existson the first boundary B1. On the other hand, in the data “1” state, themagnetization orientation of the magnetization inversion region 13 isthe −Y-direction, and the domain wall DW exists on the second boundaryB2.

When the data “1” is written (first write), the second write currentI_(W2) flows from the second magnetization fixed region 12 through themagnetization inversion region 13 to the first magnetization fixedregion 11. In this case, the electrons are injected or transferred fromthe first magnetization fixed region 11 to the magnetization inversionregion 13. As a result, the magnetization of the magnetization inversionregion 13 is switched, and its magnetization orientation is changed tothe −Y-direction. In coincidence with the motion direction of theelectrons, the domain wall DW is moved from the first boundary B1 to thesecond boundary B2. On the other hand, when the data “0” is written(second write), the first write current I_(W1) flows from the firstmagnetization fixed region 11 through the magnetization inversion region13 to the second magnetization fixed region 12. In this case, theelectrons are transferred from the second magnetization fixed region 12to the magnetization inversion region 13. As a result, the magnetizationof the magnetization inversion region 13 is switched, and itsmagnetization orientation is changed to the +Y-direction. In coincidencewith the motion direction of the electron, the domain wall DW is movedfrom the second boundary B2 to the first boundary B1.

Even by the structure shown in FIG. 7, the same effect as the structureexample 1 is obtained. Also, the read of the data is also similar to thestructure example 1.

As mentioned above, in the magnetic memory cell 1 according to thisexemplary embodiment, the magnetic recording layer 10 has the firstmagnetization fixed region 11, the second magnetization fixed region 12and the magnetization inversion region 13. This structure can be alsoconsidered as following. In short, a usual magneto-resistance element isfurther provided with a “First Magnetization Fixed Section”corresponding to the first magnetization fixed region 11 and a “SecondMagnetization Fixed Section” corresponding to the second magnetizationfixed region 12. The usual magneto-resistance element contains a freelayer, a pinned layer, and a non-magnetic layer put between them. Thefree layer, the first magnetization fixed section and the secondmagnetization fixed section are formed on the same flat surface. Thefirst magnetization fixed section is connected to the free layer on thefirst boundary B1, and the second magnetization fixed section isconnected to the free layer on the second boundary B2. The magnetizationorientation (first direction) of the first magnetization fixed sectionand the magnetization orientation (second direction) of the secondmagnetization fixed section are opposite to each other. The writecurrent, which planarly flows between the first magnetization fixedsection and the second magnetization fixed section, causes the domainwall to be moved between the first boundary B1 and the second boundaryB2, and the magnetization of the free layer is switched.

1-2. Circuit Configuration

The circuit configuration for making the write currents and I_(W1) andI_(W2) to flow through the magnetic memory cell 1 according to thisexemplary embodiment will be described below. FIG. 8 is a plan viewshowing one example of the circuit configuration of the magnetic memorycell 1. Although FIG. 8 shows the magnetic memory cell 1 of thestructure shown in FIG. 2, it can be applied to even the magnetic memorycell 1 of the structure shown in FIG. 3. Also, FIG. 9A is a section viewschematically showing the structure of the magnetic memory cell 1 shownin FIG. 8. Here, FIG. 9A shows the magnetic memory cell 1 of thestructure shown in FIG. 2. However, in case of the magnetic memory cell1 of the structure shown in FIG. 3, it is as shown in FIG. 9B.

The first magnetization fixed region 11 of the magnetic recording layer10 is connected through a contact 45 to a first lower electrode 41. Thesecond magnetization fixed region 12 is connected through a contact 46to a second lower electrode 42. The first lower electrode 41 isconnected to one of the source/drain of a first transistor TR1. Theother of the source/drain of the first transistor TR1 is connected to afirst bit line BL1. Also, the second lower electrode 42 is connected toone of the source/drain of a second transistor TR2. The other of thesource/drain of the second transistor TR2 is connected to a second bitline BL2. The gate of the first transistor TR1 and the gate of thesecond transistor TR2 are connected to a word line WL.

The pinned layer 30 is formed through the tunnel barrier layer 20 on themagnetization inversion region 13 of the magnetic recording layer 10. Anupper electrode 43 is formed on the pinned layer 30, and a read line 44is connected to the upper electrode 43. The direction of the read line44 is arbitrary. This read line 44 may be connected to a selectiontransistor or a ground.

FIG. 10A is a table summarily showing the data read/write method in caseof the circuit configuration shown in FIG. 8 and FIG. 9A or FIG. 9B.This shows a case of the magnetic memory cell 1 shown in FIG. 4A, FIG.4B and FIG. 5. In both of the write and the read, the word line WLconnected to a target memory cell is selected, and its potential is setto “High”. Consequently, the first transistor TR1 and the secondtransistor TR2 are turned ON.

When the data “1” is written, the potentials of the first bit line BL1and the second bit line BL2 are set to “High” and “Low”, respectively.As a result, the first write current IW1 flows from the first bit lineBL1 through the first transistor TR1, the magnetic recording layer 10and the second transistor TR2 to the second bit line BL2. On the otherhand, when the data “0” is written, the potentials of the first bit lineBL1 and the second bit line BL2 are set to “Low” and “High”,respectively. As a result, the second write current IW2 flows from thesecond bit line BL2 through the second transistor TR2, the magneticrecording layer 10 and the first transistor TR1 to the first bit lineBL1.

When the data is read, for example, the potential of the first bit lineBL1 is set to “High”, and the second bit line BL2 is set to “Open”.Consequently, the read current flows from the first bit line BL1 throughthe first transistor TR1 and the MTJ to the read line 44. Or, the firstbit line BL1 is set to “Open”, and the potential of the second bit lineBL2 is set to “High”. Consequently, the read current flows from thesecond bit line BL2 through the second transistor TR2 and the MTJ to theread line 44.

It should be noted that the case of the magnetic memory cell 1 shown inFIG. 6A, FIG. 6B and FIG. 7 is as shown in FIG. 10B. FIG. 10B is a tablesummarily indicating the data read/write method in case of the circuitconfiguration shown in FIG. 8 and FIG. 9A or FIG. 9B. Excluding that thedirection of the write current is opposite between a case where the data“1” is written and a case where the data “0” is written, theconfiguration is similar to a case of FIG. 10A. Thus, its description isomitted.

A peripheral circuit for controlling the word line WL, the first bitline BL1 and the second bit line BL2 would be properly designed by oneskilled in the art. FIG. 11 is a circuit block diagram showing oneexample of the configuration of the peripheral circuit.

In FIG. 11, a MRAM 50 has a memory cell array 51 in which the abovemagnetic memory cells 1 are arranged in a matrix. This memory cell array51 includes reference cells 1 r, one of which is referred when the datais read, together with the magnetic memory cells 1 used to record thedata. The basic structure of the reference cell 1 r is equal to that ofthe magnetic memory cell 1. In each magnetic memory cell 1, the readline 44 is assumed to be connected to a ground line. Also, as mentionedabove, one word line and a bit line pair (the first bit line BL1 and thesecond bit line BL2) are laid for each of the magnetic memory cells 1.

The plurality of word lines WL are connected to an X selector 52. The Xselector 52 selects one word line WL connected to a target memory cell 1s as a selection word line WLs from the plurality of word lines WL, inboth of the cases of the data write and the data read.

The plurality of first bit lines BL1 are connected to a Y-sidetermination circuit 54, and the plurality of second bit lines BL2 areconnected to a Y selector 53. The Y selector 53 selects one second bitline BL2 connected to the target memory cell 1 s, as a second selectionbit line BL2 s, from the plurality of second bit lines BL2, when thedata is written. The Y-side termination circuit 54 selects one first bitline BL1 connected to the target memory cell 1 s, as a first selectionbit line BL1 s, from the plurality of first bit lines BL1, when the datais written. In this way, the target memory cell 1 s is selected.

A Y-side current source circuit 55 is a current source for outputting orinputting predetermined write current I_(W1) or I_(W2) to or from theselected second bit line BL2 s, when the data is written. This Y-sidecurrent source circuit 55 contains a current selector unit fordetermining a direction of the write current, and a constant currentsource for supplying a constant current. A Y-side power source circuit56 supplies a predetermined voltage to the Y-side termination circuit54, when the data is written. As a result, the write current I_(W1) orI_(W2) supplied by the Y-side current source circuit 55 flow to the Yselector 53 on the basis of the data written to the target memory cell 1s or flow out from the Y selector 53. The X selector 52, the Y selector53, the Y-side termination circuit 54, the Y-side current source circuit55 and the Y-side power source circuit 56 constitute a “Write CurrentSupplying Circuit” for supplying the write current I_(W1) or I_(W2) tothe magnetic memory cell 1.

When the data is read, the first bit line BL1 is set to “Open”. A readcurrent load circuit 57 makes a predetermined read current to flowthrough the selected second bit line BL2, when the data is read. Also,the read current load circuit 57 makes a predetermined current to flowthrough a reference second bit line BL2 r connected to the referencecell 1 r. A sense amplifier 58 reads the data from the target memorycell is in accordance with a potential difference between the referencesecond bit line BL2 r and the selected second bit line BL2 r, andoutputs the data.

1-3. Fixation of Magnetization

The method of fixing the magnetizations of the first magnetization fixedregion 11 and the second magnetization fixed region 12 will be describedbelow. As the method of fixing the magnetization, there could beconsidered the following three patterns: an exchange coupling, a staticcoupling and a magnetic anisotropy.

(Exchange Coupling)

The structure example shown in FIG. 4B is exemplified. FIG. 12 is a sideview schematically showing the magnetic memory cell 1 that contains amagnetization fixing means. This magnetic memory cell 1 contains a firstmagnetic substance body 61 and a second magnetic substance body 62 asthe magnetization fixing means. The first magnetic substance body 61adds a bias magnetic field of the +Y-direction to the firstmagnetization fixed region 11. On the other hand, the second magneticsubstance body 62 applies a bias magnetic field of the −Y-direction tothe second magnetization fixed region 12.

Specifically, the first magnetic substance body 61 includes aferromagnetic layer having magnetization in the +Y-direction, and theferromagnetic layer is formed to be adhered to the first magnetizationfixed region 11. In this first magnetic substance body 61, themagnetization orientation of the first magnetization fixed region 11 isfixed to the +Y-direction through “Exchange Coupling”. On the otherhand, the second magnetic substance body 62 includes a ferromagneticlayer having magnetization in the −Y-direction, and the ferromagneticlayer is formed to be adhered to the second magnetization fixed region12. In this second magnetic substance body 62, the magnetizationorientation of the second magnetization fixed region 12 is fixed to the−Y-direction through the exchange coupling.

As shown in FIG. 12, the first magnetic substance body 61 is alamination film of, for example, CoFe/PtMn. This configuration of thelamination film is generally used in the pinned layer. As themagnetization orientation of the pinned layer is fixed, themagnetization orientation of a CoFe layer is firmly fixed to the+Y-direction, as a source to fix the magnetization orientation of thefirst magnetization fixed region 11. Also, the second magnetic substancebody 62 is a lamination film of, for example, CoFe/Ru/CoFe/PtMn. Theconfiguration of its upper half is similar to that of the first magneticsubstance body 61, and the magnetization orientation of a CoFe layer isfixed to the +Y-direction. The CoFe layer of the lower portion isanti-ferromagnetically coupled to the CoFe layer in the upper portionthrough a Ru layer, and its magnetization orientation is fixed to the−Y-direction. The CoFe layer having the magnetization of this−Y-direction is adhered to the second magnetization fixed region 12.

In this way, in FIG. 12, the film configuration is different between thefirst magnetic substance body 61 and the second magnetic substance body62. This is because the bias magnetic fields opposite to each other arerequired to be applied to the first magnetization fixed region 11 andthe second magnetization fixed region 12. Also, instead of the differentfilm configuration, the first magnetic substance body 61 and the secondmagnetic substance body 62 may be made of different materials.Similarly, the first magnetic substance body 61 and second magneticsubstance body 62 may be applied to even “Structure Examples” shown inFIG. 4A, FIG. 6A and FIG. 6B.

The magnetization fixing based on the exchange coupling may be appliedto examples other than the structure example shown in FIG. 3.

(Static Coupling)

The structure example shown in FIG. 4B is exemplified. FIG. 13 is a sideview schematically showing the magnetic memory cell 1 containingmagnetization fixing means. This magnetic memory cell 1 contains thefirst magnetic substance body 61 and the second magnetic substance body62 as the magnetization fixing means. The first magnetic substance body61 applies bias magnetic field in the +Y-direction to the firstmagnetization fixed region 11. On the other hand, the second magneticsubstance body 62 applies the bias magnetic field in the −Y-direction tothe second magnetization fixed region 12.

Specifically, the first magnetic substance body 61 includes aferromagnetic layer having, the magnetization of the −Y-directionopposite to the +Y-direction, and its ferromagnetic layer is formed awayfrom the first magnetization fixed region 11. In this first magneticsubstance body 61, the magnetization orientation of the firstmagnetization fixed region 11 is fixed to the +Y-direction by “ExchangeCoupling”. On the other hand, the second magnetic substance body 62includes a ferromagnetic layer having the magnetization in the+Y-direction opposite to the −Y-direction, and its ferromagnetic layeris formed away from the second magnetization fixed region 12. In thissecond magnetic substance body 62, the magnetization orientation of thesecond magnetization fixed region 12 is fixed to the −Y-direction by theexchange coupling.

As shown in FIG. 13, the second magnetic substance body 62 is alamination film of, for example, CoFe/Ru/CoFe/PtMn. Also, the firstmagnetic substance body 61 is a lamination film of, for example,CoFe/PtMn. The reason why the film configuration is different betweenthe first magnetic substance body 61 and the second magnetic substancebody 62 is same as the case of the exchange coupling. Also, similarly,the first magnetic substance body 61 and the second magnetic substancebody 62 may be applied to even the structure examples shown in FIG. 4A,FIG. 6A and FIG. 6B.

FIG. 14 is a diagram schematically showing the configuration forcollectively fixing the magnetizations for the memory cells of two bits.As shown in FIG. 14, a second magnetization fixed region 12A in amagnetic recording layer 10A is placed at a position adjacent to a firstmagnetization fixed region 11B in an adjacent magnetic recording layer10B. This second magnetization fixed region 12A is coupled to the firstmagnetization fixed region 11B by the static coupling, and it ismagnetically stable. That is, the magnetization orientation of thesecond magnetization fixed region 12A and the magnetization orientationof the first magnetization fixed region 11B are mutually fixed. Themagnetization orientation of the first magnetization fixed region 11 inthe adjacent magnetic memory cell is fixed through the static couplingto the second magnetization fixed region 12B (not shown). It should benoted that there is not adjacent magnetic memory cell in the end of thememory cell array. Accordingly, in that case, the method as shown inFIG. 13 is used to fix the magnetization.

The magnetization fixing based on the static coupling may be applied tothe structure examples shown in FIG. 4A, FIG. 6A and FIG. 6B.

(Magnetization Fixing of Using Shape of Magnetic Substance)

With regard to the structure examples shown in FIG. 4A, FIG. 4B, FIG. 6Aand FIG. 6B, the above exchange coupling and static coupling may not bealways applied. FIG. 15 is a diagram schematically showing the magneticmemory cell 1 in which the shape of the magnetic substance body is usedto carry out the magnetization fixing. As shown in FIG. 15, the firstmagnetization fixed region 11 and the second magnetization fixed region12 are made partially close to each other to a degree that the firstmagnetization fixed region 11 and the second magnetization fixed region12 are statically coupled. Thus, the magnetization orientations of thefirst magnetization fixed region 11 and the second magnetization fixedregion 12 are fixed opposite to each other. As the portions it ispreferable that it is the ends that are made close to each other.

(Magnetization Fixing of Using Auxiliary Magnetic Substance Body)

Also, FIG. 16 is a diagram schematically showing the magnetic memorycell 1 in which an auxiliary magnetic substance body is used to carryout the magnetization fixing. As shown in FIG. 16, the auxiliarymagnetic substance body 15 that is statically coupled to both of thefirst magnetization fixed region 11 and the second magnetization fixedregion 12 is arranged, to allow the magnetization directions of thefirst magnetization fixed region 11 and the second magnetization fixedregion 12 to be fixed to the directions opposite to each other.

In this case, the magnetization orientation of the auxiliary magneticsubstance body 15 may be set to the −X-direction or the +X-direction, atan initial annealing step. The magnetization orientations of the firstmagnetization fixed region 11 and the second magnetization fixed region12 may be held in the +Y-direction or the −Y-direction through thestatic coupling to the auxiliary magnetic substance body 15. This caseis preferable from the viewpoint that magnetization fixing means such asthe first magnetic substance body 61 and the second magnetic substancebody 62 are not required, resulting in reducing components. That is, the“H-shaped” magnetic recording layer 10 has the preferable shape, fromthe viewpoint of the magnetization fixing.

Also, FIG. 17 is a diagram schematically showing another magnetic memorycell 1 in which the auxiliary magnetic substance body is used to carryout the magnetization fixing. As shown in FIG. 17, external magneticfield whose orientation is same as an orientation in which themagnetization of the auxiliary magnetic substance body is fixed may beuniformly applied to the magnetic memory cell 1. For example, a magnetof several Oe is placed in a package. This placement stabilizes thefixing of the magnetization and improves thermal disturbance durability.In addition thereto, the above exchange coupling (refer to FIG. 12) andstatic coupling (refer to FIG. 13) may be applied in combination. Inthis case, the fixing of the magnetization is further stabilized.

1-4. Effect

As mentioned above, according to the present invention, a new read/writemethod is provided with regard to the randomly accessible MRAM. The datawrite is attained through the domain wall motion caused by the spintransfer inside the magnetic recording layer 10. The data read isattained by using the MTJ. Thus, the following effect will be attained.

At first, as compared with the asteroid method, an excellent selectingproperty of the memory cell is attained. In case of the asteroid method,a deviation in threshold of the write magnetic field reduces theselecting property of the memory cell in a two-dimensional memory cellarray. However, according to the spin transfer method, the write currentacts only on the target memory cell. Thus, disturbance is greatlydecreased. That is, the selection write property is improved.

Also, as compared with the asteroid method and the toggle method, ascaling property of the write current is improved. In case of theasteroid method and the toggle method, the switching magnetic fieldrequired to switch the magnetization of the magnetic recording layerbecomes greater, substantially inversely proportional to the memory cellsize. In short, as the structure of the memory cell is made finer, thewrite current tends to be increased. However, according to the spintransfer method, a threshold of the magnetization switching depends on acurrent density. As the memory cell size is contracted, the currentdensity is increased. Thus, the write current can be decreased inassociation with the finer structure of the memory cell. In other words,even if the memory cell size is contracted, the write current is notrequired to be increased. In this meaning, the scaling property of thewrite current is improved. This is important in realization a largecapacity of the MRAM.

Also, as compared with the asteroid method and the toggle method, acurrent magnetic field conversion efficiency increases. In case of theasteroid method and the toggle method, the write current is consumed inthe form of Joule heat. In order to improve the current magnetic fieldconversion efficiency, a dedicated write interconnection such as a fluxkeeper or a yoke structure was required to be provided. However, thisleads to the complexity of a manufacturing process and the increase ofan interconnection inductance. On the other hand, according to the spintransfer method, the write current directly contributes to the spintransfer. Thus, the current magnetic field conversion efficiencyincreases. Consequently, the complexity of the manufacturing process andthe increase of the interconnection inductance are prevented.

Moreover, as compared with the conventional spin transfer magnetizationswitching, the deterioration of the MTJ (tunnel barrier layer 20) issuppressed. The conventional spin transfer magnetization switching isattained by the CPP (Current Perpendicular to Plane) method, and thewrite current is vertically transferred into the film surface. The writecurrent when a data is written is extremely larger than the readcurrent. Thus, there was a fear that the tunnel barrier layer 20 wasdestroyed due to the large current. However, according to the writemethod of the present invention, a current route at the time of read anda current route at the time of write are separated. Specifically, whenthe data is written, the write currents I_(W1) and I_(W2) do notpenetrate through the MTJ, and they flows inside the magnetic recordinglayer 10. When the data is written, the large current is not required tobe vertically transferred into the MTJ film surface. Therefore, thedeterioration of the tunnel barrier layer 20 in the MTJ is suppressed.

Moreover, the write speed increases in association with realization of afiner structure of the memory cell. This is because in the presentinvention, the data write is attained through the domain wall motioninside the magnetic recording layer 10. The fact that the memory cellsize is contracted implies that the motion distance of the domain wallDW is made shorter. Thus, the write speed increases in association withthe contraction of the memory cell size.

According to the present invention, the above-mentioned effects areobtained at the same time. In order to attain the MRAM of a highintegration, a high speed operation and a small power consumptionamount, the technique according to the present invention is very useful.

It should be noted that instead of FIG. 8, other examples areconsidered. FIG. 18A and FIG. 18 g are plan views showing the otherexamples of the circuit configuration of the magnetic memory cell 1,respectively. FIG. 18A differs from FIG. 8 in that currents are suppliedto or drawn out from two portions of each of the first magnetizationfixed region 11 and the second magnetization fixed region 12. However,since their operations are similar to FIG. 8, their descriptions areomitted. In the circuit configuration of the magnetic memory cell 1 inFIG. 18B, two word lines of a first word line WL1 and a second word lineWL2 are provided. However, both of the first word line WL1 and thesecond word line WL2 are selected at the time of the write operation andat the time of the read operation, thereby carrying out the operationsimilar to FIG. 18A. Therefore, their descriptions are omitted.

In case of FIG. 18A and FIG. 18B, the write current flows to themagnetization inversion region 13 from both ends of the firstmagnetization fixed region 11 or both ends of the second magnetizationfixed region 12. That is, the write current flows from both end sides ofthe first magnetization fixed region 11 or both end sides of the secondmagnetization fixed region 12 in the domain wall (B1 or B2). Thus, themagnetization switching efficiency in the magnetic recording layer 10 isimproved.

Each of FIG. 19A and FIG. 19B is a circuit block diagram showing oneexample of the configuration of its peripheral circuit. When theconfiguration of FIG. 18A is used as the magnetic memory cell 1, an MRAMis realized to have the peripheral circuit shown in FIG. 19A. When theconfiguration of FIG. 18B is used as the magnetic memory cell 1, theMRAM is realized to have the peripheral circuit shown in FIG. 198. Sincean operation method of the MRAM in FIG. 19A is similar to that of FIG.11, its description is omitted. In the MRAM in FIG. 19B, the two wordlines of a first word line WL1 and a second word line WL2 are provided.However, both of the first word line WL1 and the second word line WL2are selected by the X selector 52 at the time of the write operation andat the time of the read operation. Thus, since the operation similar tothe MRAM in FIG. 19A is carried out, its description is omitted.

According to the present invention, the above-mentioned effects areobtained at the same time. In order to attain the MRAM of the highintegration, a high speed operation and a small power consumptionamount, the technique according to the present invention is very useful.

2. SECOND EXEMPLARY EMBODIMENT

As the structure to improve the write efficiency of the magneticrecording layer 10, a method of using a yoke magnetic substance body isalso considered. FIG. 20A is a plan view showing an example of theconfiguration in which the magnetic substance body (yoke magneticsubstance body) is arranged near the magnetization inversion region 13,and FIG. 20B is a side view thereof. In FIG. 20A and FIG. 20B, forexample, when the write current is supplied from the first magnetizationfixed region 11 to the second magnetization fixed region 12, a yokemagnetic substance body 63 is magnetized to the −Y-direction by itswrite current. As a result, an induced magnetic field near themagnetization inversion region 13 that is generated by the yoke magneticsubstance body 63 is oriented to the +Y-direction. On the other hand,the magnetization of the second magnetization fixed region 12 on thedrawing-out side of the write current is also oriented to the+Y-direction. In short, since the magnetic field generated by the yokemagnetic substance body 63 coincides with the direction of the writemagnetic field, the write can be efficiently performed. The yokemagnetic substance body 63 is provided on the side opposite to thepinned layer 30 with respect to the magnetization inversion region 13.

Devising a structure of the yoke magnetic substance body 63 can furtherincrease the magnetic field efficiency applied to the magnetizationinversion region 13. For example, FIG. 21A is a plan view showinganother example of the configuration in which the magnetic substancebody (yoke magnetic substance body) is arranged near the magnetizationinversion region 13, and FIG. 21B is a side view thereof. In this case,the end of the yoke magnetic substance body 63 is protruded, therebyincreasing the magnetic field that is applied to the magnetizationinversion region 13.

As mentioned above, the structure of the magnetic memory cell in whichthe yoke magnetic substance body 63 is used is effective. However, whenthe orientations of the first magnetization fixed region 11 and thesecond magnetization fixed region 12 are made opposite, the effectresulting from the yoke magnetic substance 13 is made opposite. Thus,attention should be paid to this point in designing.

3. THIRD EXEMPLARY EMBODIMENT

FIG. 22 is a plan view showing still another example of the structure ofthe magnetic memory cell. In FIG. 22, the magnetic memory cell has astructure in which the memory cells of two bits are consecutive. Themagnetic recording layer 10 includes a second magnetization inversionregion 13-2 and a third magnetization fixed region 11-2, in addition toa first magnetization fixed region 11-1, a first magnetization inversionregion 13-1 and a second magnetization fixed region 12. Each of thefirst magnetization inversion region 13-1 and the second magnetizationinversion region 13-2 is connected through the tunnel barrier layer tothe pinned layer (not shown).

The first magnetization fixed region 11-1 and the first magnetizationinversion region 13-1 are connected to each other on the first boundaryB1. The first magnetization inversion region 13-1 and the secondmagnetization fixed region 12 are connected to each other on the secondboundary B2. The first boundary B1 and the second boundary B2 arelocated on the opposite ends of the first magnetization inversion region13-1. Also, the second magnetization fixed region 12 and the secondmagnetization inversion region 13-2 are connected to each other on athird boundary B3. The second magnetization inversion region 13-2 andthe third magnetization fixed region 11-2 are connected to each other ona fourth boundary B4. The third boundary 33 and the fourth boundary B4are located on the opposite ends of the second magnetization inversionregion 13-2.

In FIG. 22, the first magnetization fixed region 11-1, the secondmagnetization fixed region 12 and the third magnetization fixed region11-2 are formed to be substantially parallel to each other along theY-direction. The first magnetization inversion region 13-1 is formedalong the X-direction for linkage between the first magnetization fixedregion 11-1 and the second magnetization fixed region 12. The secondmagnetization inversion region 13-2 is formed along the X-direction forlinkage between the second magnetization fixed region 12 and the thirdmagnetization fixed region 11-2.

The magnetization orientations of the first magnetization inversionregion 13-1 and the second magnetization inversion region 13-2 can beswitched, and they are allowed to be oriented to the +Y-direction or the−Y-direction in accordance with the given magneto-crystallineanisotropy. The magnetization orientations of the first magnetizationfixed region 11-1 and the third magnetization fixed region 11-2 arefixed to the −Y-direction. Also, the magnetization orientation of thesecond magnetization fixed region 12 is fixed to the +Y-direction. Thatis, the magnetization orientation of the first magnetization fixedregion 11-1, the magnetization orientation of the second magnetizationfixed region 12 and the magnetization orientation of the thirdmagnetization fixed region 11-2 are alternately inverted along the shapeof the magnetic recording layer 10.

In FIG. 22, the first magnetization fixed region 11-1 is connectedthrough the first transistor TR1 to the first bit line BL1. The secondmagnetization fixed region 12 is connected through the second transistorTR2 to the second bit line BL2. The third magnetization fixed region11-2 is connected through the third transistor TR3 to the third bit lineBL3. For example, when a data is written to the first magnetizationinversion region 13-1, the first transistor TR1 and the secondtransistor TR2 are turned ON, and the write current in a directioncorresponding to the write data may be supplied to the first bit lineBL1 and the second bit line BL2. Also, when a data is written to thesecond magnetization inversion region 13-2, the second transistor TR2and the third transistor TR3 are turned ON, and the write current in adirection corresponding to the write data may be supplied to the secondbit line BL2 and the third bit line BL3. The data read can be attainedby, for example, a cross point method. Even by such a structure, theeffect similar to the first exemplary embodiment is obtained.

The structure in which the memory cells of n bits (n is a naturalnumber) are consecutive is represented as follows, when it isgeneralized. The magnetic recording layer includes n magnetizationinversion regions A1 to An and (n+1) magnetization fixed regions B1 toBn+1. The n magnetization inversion regions A1 to An and the (n+1)magnetization fixed regions B1 to Bn+1 are alternately arranged. Inshort, the i^(th) (i is an integer between 1 and n) magnetizationinversion region Ai is formed for linkage between the i^(th)magnetization fixed region Bi and the (i+1)^(th) magnetization fixedregion Bi+1. The magnetization orientation of the i^(th) magnetizationfixed region B1 and the magnetization orientation of the (i+1)^(th)magnetization fixed region Bi+1 are fixed to the directions opposite toeach other. In short, the magnetization orientations of the (n+1)magnetization fixed regions B1 to B(n+1) are alternately inverted alongthe shape of the magnetic recording layer. Also, n MTJs are formed inthe n magnetization inversion regions A1 to An, respectively. Moreover,the (n+1) magnetization fixed regions B1 to Bn+1 are connected throughthe (n+1) transistors to the (n+1) bit lines BL1 to BLn+1, respectively.When a data is written to the i^(th) magnetization inversion region Ai,the write current in a direction corresponding to the write data issupplied to the i^(th) bit line BLi and the (i+1)^(th) bit line BLi+1.The data read can be attained by, for example, the cross point method.Even by such a structure, the effect similar to the first exemplaryembodiment is obtained.

4. FOURTH EXEMPLARY EMBODIMENT

FIG. 23 is a side view showing the structure of the magnetic memory cellaccording to this exemplary embodiment. In this exemplary embodiment,the magnetic recording layer 10 is configured by a syntheticanti-ferromagnetic (SAF) layer. Specifically, the magnetic recordinglayer 10 includes a first ferromagnetic layer 10 a and a secondferromagnetic layer 10 b, which are anti-ferromagnetically coupledthrough an intermediate layer 14. The intermediate layer 14 is anon-magnetic layer, e.g., a Ru layer. The first ferromagnetic layer 10 ahas a first magnetization fixed region 11 a, a second magnetizationfixed region 12 a and a magnetization fixed region 13 a sandwichedbetween the first and second magnetization fixed regions 11 a and 12 a.Also, the second ferromagnetic layer 10 b has a first magnetizationfixed region 11 b, a second magnetization fixed region 12 b and amagnetization fixed region 13 b sandwiched between the first and secondmagnetization fixed regions 11 b and 12 b.

The magnetization orientations of the first magnetization fixed regions11 a and 11 b are opposite. Also, the magnetization orientations of thesecond magnetization fixed regions 12 a and 12 b are opposite. Also, themagnetization orientations of the magnetization inversion regions 13 aand 13 b are opposite. The magnetizations of the magnetization inversionregions 13 a and 13 b can be switched, and they are oriented to the+Y-direction or the −Y-direction. When one of the magnetizations of themagnetization inversion regions 13 a and 13 b is switched, the othermagnetization is also switched. The magnetization inversion region 13 aof the first ferromagnetic layer 10 a is adjacent to the pinned layer 30through the tunnel barrier layer 20. FIG. 23 shows “0-state” in whichthe magnetization of the magnetization inversion region 13 a and themagnetization of the pinned layer 30 are parallel. In this case, thedomain wall DW exists on the second boundary B2.

The data write is carried out similarly to the above-mentioned exemplaryembodiments. For example, when the data “1” is written, the writecurrents flow from the second magnetization fixed regions 12 a and 12 bto the first magnetization fixed regions 11 a and 11 b inside themagnetic recording layer 10, respectively. As a result, themagnetizations of the magnetization inversion regions 13 a and 13 b areboth switched, and the domain wall DW is moved to the second boundaryB2. The data read is carried out by using the pinned layer 30 andsensing the magnetization orientation of the magnetization inversionregion 13 a in the first ferromagnetic layer 10 a. Even by such astructure, the effect similar to the first exemplary embodiment isobtained. Moreover, the reduction of influence of an external magneticfield by the SAF layer is expected.

5. FIFTH EXEMPLARY EMBODIMENT

Although FIG. 8 shows the circuit configuration of the magnetic memorycell having the two transistors TR1 and TR2, the circuit configurationis not limited thereto. FIG. 24 is a plan view showing the circuitconfiguration of the magnetic memory cell that has only one transistorTR. Also, FIG. 25 is a sectional view schematically showing thestructure of the magnetic memory cell shown in FIG. 24.

The first magnetization fixed region 11 in the magnetic recording layer10 is connected through a contact 45 to a first lower electrode 41, andthe second magnetization fixed region 12 is connected through a contact46 to a second lower electrode 42. The first lower electrode 41 isconnected to one of the source/drain of the transistor TR. The other ofthe source/drain of the transistor TR is connected to the bit line BL.Also, the second lower electrode 42 is connected to the ground. The gateof the transistor TR is connected to the word line WL.

When a data is written, the word line WL connected to a target memorycell is selected, and the transistor TR connected to the target memorycell is turned on. The direction of the write current flowing throughthe bit line BL is changed in accordance with the write data. Forexample, when the data “1” is written, a write current supplying circuitsupplies the first write current IW₁ to the bit line BL. In this case,the first write current IW₁ flows from the bit line BL through thetransistor TR, the first magnetization fixed region 11, themagnetization inversion region 13 and the second magnetization fixedregion 12 to the ground. On the other hand, when the data “0” iswritten, the write circuit supplying circuit draws out the second writecurrent IW₂ from the ground. In this case, the second write current IW₂flows from the ground through the second magnetization fixed region 12,the magnetization inversion region 13, the first magnetization fixedregion 11 and the transistor TR to the bit line BL. The data read can beattained by, for example, the cross point method. Even by such astructure, the effect similar to the first exemplary embodiment isobtained.

6. SIXTH EXEMPLARY EMBODIMENT

The data can be also written to the magnetic memory cell 1 in theabove-mentioned exemplary embodiments by auxiliaryly applying the writemagnetic field from the outside. FIG. 26 is a plan view showing theprinciple of applying the write magnetic field from the outside andwriting the data to the magnetic memory cell. In this case, the MRAMcontains a write interconnection 90 that is magnetically coupled to themagnetic recording layer 10 (magnetization inversion region 13). Theother components are similar to the case of FIG. 7.

When the data “1” is written, similarly to the case of FIG. 7, a secondwrite current I_(W2)′ (whose current value is smaller than the secondwrite current in FIG. 7) is supplied to the magnetic recording layer 10in the −X-direction. Simultaneously, a third write current is suppliedto the write interconnection 90 in the −X-direction. The write magneticfield generated by the third write current I_(W2) is applied to themagnetization inversion region 13. The direction of the write magneticfield is the −Y-direction at the position of the magnetization inversionregion 13. As a result, the magnetization of the magnetization inversionregion 13 is switched, and the domain wall DW is moved from the firstboundary B1 to the second boundary B2. Thus, the data “1” is written.

On the other hand, when the data “0” is written, similarly to the caseof FIG. 7, a first write current (whose current value is smaller thanthe first write current I_(W1) in FIG. 7) is supplied to the magneticrecording layer 10 in the +X-direction. Simultaneously, a fourth writecurrent I_(W4) is supplied to the write interconnection 90 in the+X-direction. The write magnetic field generated by the fourth writecurrent I_(W4) is applied to the magnetization inversion region 13. Theorientation of the write magnetic field is the +Y-direction at theposition of the magnetization inversion region 13. As a result, themagnetization of the magnetization inversion region 13 is switched, andthe domain wall DW is moved from the second boundary B2 to the firstboundary B1. Thus, the data “0” is written.

In this case, the value of the write current directly flowing throughthe magnetic recording layer 10 can be decreased, as compared with thecase of FIG. 7. Also, as compared with the case in which themagnetization switching is carried out only on the write interconnection90, the current flowing through the write interconnection 90 can bedecreased. With those mechanisms, the maximum current of each ofelements related to a current source can be suppressed to a small value.

The peripheral circuit for controlling the word line WL, a write wordline WWL (the write interconnection 90 in FIG. 26), the first bit lineBL1 and the second bit line BL2 may be properly designed by one skilledin the art. FIG. 27 is a circuit block diagram showing one example ofthe configuration of the peripheral circuit. Here, in addition to thecircuit in FIG. 11, an X power supply circuit 59 for supplying the writecurrent through the X selector 52 to the write word line WWL and anX-side termination circuit 60 for terminating the write word line WWL atthe time of the write operation are added.

In the write operation, as well as the operation of the circuit in FIG.11, the X selector 52 selects the write word line WWL (writeinterconnection 90) on a selection cell, and the X power supply circuit59 supplies the write current (third write current I_(W1), or fourthwrite current I_(W4)) in a direction corresponding to the write data.

It should be noted that the above-mentioned first to sixth exemplaryembodiments can be properly combined unless any technical contradictionis not generated.

The present invention is not limited to the above-mentioned exemplaryembodiments, and it is evident that variations and modifications withoutdeparting from the scope and spirit of the present invention can becarried out.

According to the present invention, a new data write method with regardto the MRAM is provided. Specifically, the write current does not flowin the direction penetrating the MTJ, and it flatly and planarly flowsinside the magnetic recording layer. Through the spin transfer effectcaused by the spin electrons, the magnetization of the magnetizationinversion region inside the magnetic recording layer is switched to theorientation according to the direction of the write current. At thistime, the domain wall inside the magnetic recording layer isreciprocated in the manner of “Seesaw” between the first boundary andthe second boundary according to the motion direction of the electronsserving as the write current. In short, the domain wall is moved insidethe magnetization inversion region (Domain Wall Motion).

At the time of write, since the write current does not penetrate theMTJ, the deterioration of the tunnel barrier layer in the MTJ issuppressed. Also, the data write is carried out by the spin transfermethod. Thus, the write current is decreased in association with thecontraction of the memory cell size. Moreover, as the memory cell sizeis contracted, the motion distance of the domain wall is made shorter.Therefore, the write speed is increased in association with the finerstructure of the memory cell.

The invention claimed is:
 1. A magnetic memory cell comprising: amagnetic recording layer which is a ferromagnetism layer; and a pinnedlayer connected with said magnetic recording layer through anon-magnetic layer, wherein said magnetic recording layer comprises: amagnetization inversion region having a magnetization invertible into afirst direction or a second direction and provided to overlap saidpinned layer; a first magnetization fixed region connected with a firstboundary of said magnetization inversion region and having amagnetization whose orientation is fixed on the first direction; and asecond magnetization fixed region connected with a second boundary ofsaid magnetization inversion region and having a magnetization whoseorientation is fixed on the second direction, and the first directionand the second direction are opposite to each other, wherein saidmagnetization inversion region, said first magnetization fixed regionand said second magnetization fixed region are provided in a same layer,wherein said magnetization inversion region, said first magnetizationfixed region and said second magnetization fixed region are arranged inan H-shaped form.
 2. The magnetic memory cell according to claim 1,wherein one of the first direction and the second direction iscoincident with an orientation of a magnetization of said pinned layer.3. The magnetic memory cell according to claim 1, further comprising: afirst magnetic substance body configured to apply a bias magnetic fieldof the first direction to said first magnetization fixed region; and asecond magnetic substance body configured to apply a bias magnetic fieldof the second direction to said second magnetization fixed region. 4.The magnetic memory cell according to claim 3, wherein said firstmagnetic substance body and said second magnetic substance body areprovided to be in contact with said first magnetization fixed region andsaid second magnetization fixed region, respectively, and an orientationof a magnetization of said first magnetic substance body is the firstdirection and an orientation of a magnetization of said second magneticsubstance body is the second direction.
 5. The magnetic memory cellaccording to claim 3, wherein said first magnetic substance body andsaid second magnetic substance body are provided to be away said firstmagnetization fixed region and said second magnetization fixed region,respectively, and an orientation of a magnetization of said firstmagnetic substance body is opposite to the first direction, and anorientation of a magnetization of said second magnetic substance body isopposite to the second direction.
 6. The magnetic memory cell accordingto claim 1, wherein said first magnetization fixed region and saidsecond magnetization fixed region have magnetic anisotropy of a sameorientation, and said magnetization inversion region has magneticanisotropy of a same orientation as one of the magnetizationorientations of said first magnetization fixed region and said secondmagnetization fixed region.
 7. The magnetic memory cell according toclaim 6, wherein an external magnetic field is applied in a samedirection of as one of the first direction and the second direction. 8.The magnetic memory cell according to claim 1, wherein a first writecurrent flows from said first magnetization fixed region to said secondmagnetization fixed region through said magnetization inversion regionin case of a first write operation, and a second write current flowsfrom said second magnetization fixed region to said first magnetizationfixed region through said magnetization inversion region in case of asecond write operation.
 9. The magnetic memory cell according to claim8, wherein a domain wall is positioned in said first boundary in saidmagnetic recording layer through the first write operation, and thedomain wall is positioned in said second boundary in said magneticrecording layer through the second write operation.
 10. The magneticmemory cell according to claim 8, wherein the first direction iscoincident with a magnetization orientation of said pinned layer, themagnetization orientation of said magnetization inversion region isturned to the second direction through the first write operation, andthe magnetization orientation of said magnetization inversion region isturned to the first direction through the second write operation. 11.The magnetic memory cell according to claim 1, wherein a read currentflows between one of said first magnetization fixed region and saidsecond magnetization fixed region and said pinned layer through saidmagnetization inversion region and said non-magnetic layer in case of aread operation.
 12. The magnetic memory cell according to claim 1,further comprising: a first auxiliary magnetic substance bodystatic-coupled with said first magnetization fixed region and saidsecond magnetization fixed region.
 13. The magnetic memory cellaccording to claim 1, wherein said first magnetization fixed region isstatic-coupled with said second magnetization fixed region.
 14. Amagnetic random access memory comprising: a magnetic memory cell; a bitline connected with said magnetic memory cell; and a word line connectedwith said magnetic memory cell, wherein said magnetic memory cellcomprises: a magnetic recording layer which is a ferromagnetism layer;and a pinned layer connected with said magnetic recording layer througha non-magnetic layer, wherein said magnetic recording layer comprises: amagnetization inversion region having a magnetization invertible into afirst direction or a second direction and provided to overlap saidpinned layer; a first magnetization fixed region connected with a firstboundary of said magnetization inversion region and having amagnetization whose orientation is fixed on the first direction; and asecond magnetization fixed region connected with a second boundary ofsaid magnetization inversion region and having a magnetization whoseorientation is fixed on the second direction, and the first directionand the second direction are opposite to each other, wherein said bitline comprises: a first bit line connected with said first magnetizationfixed region through a first transistor, said magnetic random accessmemory further comprises: a write current supplying circuit connectedwith said first bit line and configured to control a current flowingthrough said magnetic memory cell based on a write data, wherein saidmagnetization inversion region, said first magnetization fixed regionand said second magnetization fixed region are provided in a same layer,wherein said magnetization inversion region, said first magnetizationfixed region and said second magnetization fixed region are arranged inan H-shaped form.
 15. The magnetic random access memory according toclaim 14, wherein said bit line further comprises: a second bit lineconnected with said second magnetization fixed region through a secondtransistor, wherein said word line is connected with gates of said firstand second transistors, said write current supplying circuit isconnected with said first bit line and said second bit line, in case ofa first write operation, said word line is selected, and said writecurrent supplying circuit supplies a first write current from said firstbit line to said second bit line through said first transistor, saidmagnetic recording layer and said second transistor, and in case of asecond write operation, said word line is selected, and said writecurrent supplying circuit supplies a second write current from saidsecond bit line to said first bit line through said second transistor,said magnetic recording layer and said first transistor.
 16. Themagnetic random access memory according to claim 14, wherein said firstbit line is connected with said first magnetization fixed region throughsaid first transistor and a third transistor, and said bit line furthercomprises: a second bit line connected with said second magnetizationfixed region through a second transistor and a fourth transistor,wherein said word line comprises: a first word line connected to gatesof said first and second transistors; and a second word line connectedto gates of said third and fourth transistors, said write currentsupplying circuit is connected with said first bit line and said secondbit line, in case of a first write operation, said first and second wordlines are selected, and said write current supplying circuit supplies afirst write current from said first bit line to said second bit linethrough said first transistor and said third transistor, said magneticrecording layer, and said second transistor and a said fourthtransistor, and in case of a second write operation, said first andsecond word lines are selected, and said write current supplying circuitsupplies a second write current from said second bit line to said firstbit line through said second transistor and said fourth transistor, saidmagnetic recording layer, and said first transistor and said thirdtransistor.
 17. The magnetic random access memory according to claim 14,wherein said bit line further comprises: a second bit line connectedwith said second magnetization fixed region through a second transistor,wherein said word line is connected with gates of said first and secondtransistors, said first magnetization fixed region and said firsttransistor are connected through a plurality of interconnections, saidsecond magnetization fixed region and said second transistor areconnected through a plurality of interconnections, said write currentsupply circuit is connected with said first bit line and said second bitline, in case of a first write operation, said word line is selected,and said write current supplying circuit supplies a first write currentfrom said first bit line to said second bit line through said firsttransistor, said first auxiliary interconnection, said magneticrecording layer and said second transistor, and in case of a secondwrite operation, said word line is selected, and said write currentsupplying circuit supplies a second write current from said second bitline to said first bit line through said second transistor, said secondauxiliary interconnection, said magnetic recording layer and said firsttransistor.
 18. The magnetic random access memory according to claim 14,where said word line is connected with a gate of said first transistor,said write current supplying circuit is connected with said first bitline, said second magnetization fixed region of said magnetic memorycell is grounded, in case of a first write operation, said word line isselected, and said write current supplying circuit supplies the firstwrite current from said bit line to said magnetic memory cell throughsaid transistor, and in case of a second write operation, said word lineis selected, and said write current supplying circuit draws out thesecond write current from said magnetic memory cell through saidtransistor and said bit line.
 19. An operation method of a magneticrandom access memory, wherein said magnetic random access memorycomprises a magnetic memory cell, said magnetic memory cell comprises amagnetic recording layer which is a ferromagnetic layer, and a pinnedlayer connected with said magnetic recording layer through anon-magnetic layer, said magnetic recording layer comprises amagnetization inversion region having a magnetization invertible in afirst direction and a second direction, and provided to overlap saidpinned layer, a first magnetization fixed region connected with a firstboundary of said magnetization inversion region and having amagnetization whose orientation is fixed to the first direction, and asecond magnetization fixed region connected with a second boundary ofsaid magnetization inversion region and having a magnetization whoseorientation is fixed to a second direction, and the first direction isparallel or anti-parallel to the magnetization orientation of saidpinned layer, said operation method comprising: making a first writecurrent flow from said first magnetization fixed region to said secondmagnetization fixed region through said magnetization inversion regionin case of writing a first data; and making a second write current flowfrom said second magnetization fixed region to said first magnetizationfixed region through said magnetization inversion region in case ofwriting a second data, wherein said magnetization inversion region, saidfirst magnetization fixed region and said second magnetization fixedregion are provided in a same layer, wherein said magnetizationinversion region, said first magnetization fixed region and said secondmagnetization fixed region are arranged in an H-shaped form.
 20. Theoperation method according to claim 19, further comprising: making aread current flow between one of said first magnetization fixed regionand said second magnetization fixed region and said pinned layer throughsaid magnetization inversion region and said non-magnetic layer, whenreading said first data or said second data stored in said magneticmemory cell.